The present invention relates to a method of treatment of allergic diseases, and more particularly it relates to a method of treating a patient suffering from allergic diseases, which comprises administering to said patient an effective amount of a pharmaceutical composition in dosage unit form comprising a dry powder of guava leaves or an extract obtained from guava leaves by a solvent.
Recently, the allergic diseases such as bronchial asthma, atopic dermatitis, allergic rhinitis and pollenosis are increasing. These allergic diseases are, in most cases, traceable to the I type allergic reaction, and it is known that the allergic diseases are induced by the liberation of a chemical transfer substance which takes place when an immunoglobulin E antibody against allergen, which has been produced in large, is combined with allergen on the surfaces of the mast cells.
Hitherto, steroidal preparations have been generally used as therapeutic agents for allergic diseases, but such steroidal preparations have strong side-effects and require circumspection for their application.
Guava (botanical name: Psidium guajava L.) is a plant belonging to the family Myrtaceae, which is native to South America. This plant has been known from long ago as a medicinal tree, and its leaves have been used as a salve for wounds and a medicine for the stomach and bowels. The solvent extract obtained from the guava leaves are also used for cosmetics (see Japanese Patent Application Laid-Open (Kokai) No. 5-245837). However, it has not been known that the guava leaves have an antiallergic activity.
As a result of the present inventors' extensive researches of screening of the available medicinal plants for solving the above-mentioned problems, it has been found that a dry powder of guava leaves or a solvent extraction obtained from the guava leaves has an antiallergic activity. The present invention has been attained on the basis of this finding.